Thuyacontha began his career in the Sri Lanka Air Force on 17 May 1988 as an Officer Cadet in the 19th Intake and was commissioned as a Pilot Officer in the General Duties Pilot Branch in 1990. After completing his training that same year, he was deployed as an operational pilot flying Bell 212/412 helicopters.
In 2001, he joined the No. 9 Attack Helicopter Squadron at Sri Lanka Air Force Base Hingurakgoda, initially serving as the Second in Command before becoming the Commanding Officer in 2005. Over his extensive career, he participated in all major operations, including the humanitarian campaign to liberate the North and East, logging over 7,000 flying hours as an Operations, VIP, and Attack Helicopter Pilot.
Additionally, Thuyacontha served as the Defence Adviser at the Sri Lankan High Commission in Islamabad, Pakistan, for two years and as the Chief Instructor at the Defence Services Command and Staff College in 2014.
For his acts of gallantry and bravery during humanitarian operations, he has been awarded several decorations, including the “Weera Wickrama Vibhushanaya” (WWV), “Rana Wickrama Padakkama” (RWP), and “Rana Sura Padakkama” (RSP).